SLE is an unpredictable disease characterized by flare-ups, usually requiring an increase in lupus medications. The current laboratory tests available to doctors are unsatisfactory, because they miss over 50% of flare-ups, and because they are sometimes abnormal in patients who are doing well. This is a research effort to find better blood tests to predict disease flare-ups. This project was completed in January, 1999. Samples have been sent out for laboratory testing at Colorado Coagulation and at Dr. Gunnar Sturfeldt's laboratory in Sweden.